[PATCH 07/10] [vfs] replace ->follow_link() with new method that could stay in RCU mode

From: Al Viro
Date: Tue Nov 17 2015 - 18:04:06 EST

From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

new method: ->get_link(); replacement of ->follow_link(). The differences
are:
* inode and dentry are passed separately
* might be called both in RCU and non-RCU mode;
the former is indicated by passing it a NULL dentry.
* when called that way it isn't allowed to block
and should return ERR_PTR(-ECHILD) if it needs to be called
in non-RCU mode.

It's a flagday change - the old method is gone, all in-tree instances
converted. Conversion isn't hard; said that, so far very few instances
do not immediately bail out when called in RCU mode. That'll change
in the next commits.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
Documentation/filesystems/Locking | 4 +--
Documentation/filesystems/porting | 6 ++++
drivers/staging/lustre/lustre/llite/symlink.c | 8 +++--
fs/9p/vfs_inode.c | 17 +++++++---
fs/9p/vfs_inode_dotl.c | 14 ++++++---
fs/affs/symlink.c | 4 +--
fs/autofs4/symlink.c | 13 +++++---
fs/btrfs/inode.c | 2 +-
fs/ceph/inode.c | 2 +-
fs/cifs/cifsfs.c | 2 +-
fs/cifs/cifsfs.h | 4 +--
fs/cifs/link.c | 6 ++--
fs/coda/cnode.c | 2 +-
fs/configfs/symlink.c | 11 +++++--
fs/dcache.c | 2 +-
fs/ecryptfs/inode.c | 12 +++++--
fs/ext2/symlink.c | 4 +--
fs/ext4/symlink.c | 13 +++++---
fs/f2fs/namei.c | 16 ++++++----
fs/fuse/dir.c | 9 ++++--
fs/gfs2/inode.c | 15 ++++++---
fs/hostfs/hostfs_kern.c | 10 ++++--
fs/jffs2/symlink.c | 2 +-
fs/jfs/symlink.c | 4 +--
fs/kernfs/symlink.c | 11 +++++--
fs/libfs.c | 9 +++---
fs/minix/inode.c | 2 +-
fs/namei.c | 45 +++++++++++++++++----------
fs/ncpfs/inode.c | 2 +-
fs/nfs/symlink.c | 9 ++++--
fs/nilfs2/namei.c | 2 +-
fs/ocfs2/symlink.c | 2 +-
fs/overlayfs/inode.c | 12 ++++---
fs/proc/base.c | 22 +++++++------
fs/proc/inode.c | 7 +++--
fs/proc/namespaces.c | 9 ++++--
fs/proc/self.c | 7 +++--
fs/proc/thread_self.c | 7 +++--
fs/reiserfs/namei.c | 2 +-
fs/squashfs/symlink.c | 2 +-
fs/sysv/inode.c | 2 +-
fs/ubifs/file.c | 2 +-
fs/xfs/xfs_iops.c | 8 +++--
include/linux/fs.h | 6 ++--
mm/shmem.c | 12 ++++---
45 files changed, 232 insertions(+), 130 deletions(-)

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 06d4434..4fba54b 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -50,7 +50,7 @@ prototypes:
int (*rename2) (struct inode *, struct dentry *,
struct inode *, struct dentry *, unsigned int);
int (*readlink) (struct dentry *, char __user *,int);
- const char *(*follow_link) (struct dentry *, void **);
+ const char *(*get_link) (struct dentry *, struct inode *, void **);
void (*put_link) (struct inode *, void *);
void (*truncate) (struct inode *);
int (*permission) (struct inode *, int, unsigned int);
@@ -83,7 +83,7 @@ rmdir: yes (both) (see below)
rename: yes (all) (see below)
rename2: yes (all) (see below)
readlink: no
-follow_link: no
+get_link: no
put_link: no
setattr: yes
permission: no (may not block if called in rcu-walk mode)
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index da398d87..77ca24d 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -509,3 +509,9 @@ in your dentry operations instead.
any symlink that might use page_follow_link_light/page_put_link() must
have inode_nohigh(inode) called before anything might start playing with
its pagecache.
+--
+[mandatory]
+ ->follow_link() is replaced with ->get_link(); same API, except that
+ * ->get_link() gets inode as a separate argument
+ * ->get_link() may be called in RCU mode - in that case NULL
+ dentry is passed
diff --git a/drivers/staging/lustre/lustre/llite/symlink.c b/drivers/staging/lustre/lustre/llite/symlink.c
index 69b2036..153fdf9 100644
--- a/drivers/staging/lustre/lustre/llite/symlink.c
+++ b/drivers/staging/lustre/lustre/llite/symlink.c
@@ -118,12 +118,14 @@ failed:
return rc;
}

-static const char *ll_follow_link(struct dentry *dentry, void **cookie)
+static const char *ll_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- struct inode *inode = d_inode(dentry);
struct ptlrpc_request *request = NULL;
int rc;
char *symname = NULL;
+ if (!dentry)
+ return ERR_PTR(-ECHILD);

CDEBUG(D_VFSTRACE, "VFS Op\n");
ll_inode_size_lock(inode);
@@ -149,7 +151,7 @@ static void ll_put_link(struct inode *unused, void *cookie)
struct inode_operations ll_fast_symlink_inode_operations = {
.readlink = generic_readlink,
.setattr = ll_setattr,
- .follow_link = ll_follow_link,
+ .get_link = ll_get_link,
.put_link = ll_put_link,
.getattr = ll_getattr,
.permission = ll_inode_permission,
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 699941e..8ba5a89 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -1223,18 +1223,25 @@ ino_t v9fs_qid2ino(struct p9_qid *qid)
}

/**
- * v9fs_vfs_follow_link - follow a symlink path
+ * v9fs_vfs_get_link - follow a symlink path
* @dentry: dentry for symlink
+ * @inode: inode for symlink
* @cookie: place to pass the data to put_link()
*/

-static const char *v9fs_vfs_follow_link(struct dentry *dentry, void **cookie)
+static const char *v9fs_vfs_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
- struct p9_fid *fid = v9fs_fid_lookup(dentry);
+ struct v9fs_session_info *v9ses;
+ struct p9_fid *fid;
struct p9_wstat *st;
char *res;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
+ v9ses = v9fs_dentry2v9ses(dentry);
+ fid = v9fs_fid_lookup(dentry);
p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);

if (IS_ERR(fid))
@@ -1452,7 +1459,7 @@ static const struct inode_operations v9fs_file_inode_operations = {

static const struct inode_operations v9fs_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = v9fs_vfs_follow_link,
+ .get_link = v9fs_vfs_get_link,
.put_link = kfree_put_link,
.getattr = v9fs_vfs_getattr,
.setattr = v9fs_vfs_setattr,
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index cb899af..0cc105d 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -899,20 +899,26 @@ error:
}

/**
- * v9fs_vfs_follow_link_dotl - follow a symlink path
+ * v9fs_vfs_get_link_dotl - follow a symlink path
* @dentry: dentry for symlink
+ * @inode: inode for symlink
* @cookie: place to pass the data to put_link()
*/

static const char *
-v9fs_vfs_follow_link_dotl(struct dentry *dentry, void **cookie)
+v9fs_vfs_get_link_dotl(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- struct p9_fid *fid = v9fs_fid_lookup(dentry);
+ struct p9_fid *fid;
char *target;
int retval;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);

+ fid = v9fs_fid_lookup(dentry);
if (IS_ERR(fid))
return ERR_CAST(fid);
retval = p9_client_readlink(fid, &target);
@@ -984,7 +990,7 @@ const struct inode_operations v9fs_file_inode_operations_dotl = {

const struct inode_operations v9fs_symlink_inode_operations_dotl = {
.readlink = generic_readlink,
- .follow_link = v9fs_vfs_follow_link_dotl,
+ .get_link = v9fs_vfs_get_link_dotl,
.put_link = kfree_put_link,
.getattr = v9fs_vfs_getattr_dotl,
.setattr = v9fs_vfs_setattr_dotl,
diff --git a/fs/affs/symlink.c b/fs/affs/symlink.c
index e3f9dc3..39d1194 100644
--- a/fs/affs/symlink.c
+++ b/fs/affs/symlink.c
@@ -20,7 +20,7 @@ static int affs_symlink_readpage(struct file *file, struct page *page)
char c;
char lc;

- pr_debug("follow_link(ino=%lu)\n", inode->i_ino);
+ pr_debug("get_link(ino=%lu)\n", inode->i_ino);

bh = affs_bread(inode->i_sb, inode->i_ino);
if (!bh)
@@ -71,7 +71,7 @@ const struct address_space_operations affs_symlink_aops = {

const struct inode_operations affs_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.setattr = affs_notify_change,
};
diff --git a/fs/autofs4/symlink.c b/fs/autofs4/symlink.c
index da0c334..39e6f0b 100644
--- a/fs/autofs4/symlink.c
+++ b/fs/autofs4/symlink.c
@@ -12,10 +12,15 @@

#include "autofs_i.h"

-static const char *autofs4_follow_link(struct dentry *dentry, void **cookie)
+static const char *autofs4_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
- struct autofs_info *ino = autofs4_dentry_ino(dentry);
+ struct autofs_sb_info *sbi;
+ struct autofs_info *ino;
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+ sbi = autofs4_sbi(dentry->d_sb);
+ ino = autofs4_dentry_ino(dentry);
if (ino && !autofs4_oz_mode(sbi))
ino->last_used = jiffies;
return d_inode(dentry)->i_private;
@@ -23,5 +28,5 @@ static const char *autofs4_follow_link(struct dentry *dentry, void **cookie)

const struct inode_operations autofs4_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = autofs4_follow_link
+ .get_link = autofs4_get_link
};
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index cf917d7..48e13fd 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10118,7 +10118,7 @@ static const struct inode_operations btrfs_special_inode_operations = {
};
static const struct inode_operations btrfs_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.getattr = btrfs_getattr,
.setattr = btrfs_setattr,
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 498dcfa..da55eb8 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1756,7 +1756,7 @@ retry:
*/
static const struct inode_operations ceph_symlink_iops = {
.readlink = generic_readlink,
- .follow_link = simple_follow_link,
+ .get_link = simple_get_link,
.setattr = ceph_setattr,
.getattr = ceph_getattr,
.setxattr = ceph_setxattr,
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index cbc0f4b..4593f416 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -900,7 +900,7 @@ const struct inode_operations cifs_file_inode_ops = {

const struct inode_operations cifs_symlink_inode_ops = {
.readlink = generic_readlink,
- .follow_link = cifs_follow_link,
+ .get_link = cifs_get_link,
.put_link = kfree_put_link,
.permission = cifs_permission,
/* BB add the following two eventually */
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index c3cc160..6886328 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -120,9 +120,7 @@ extern struct vfsmount *cifs_dfs_d_automount(struct path *path);
#endif

/* Functions related to symlinks */
-extern const char *cifs_follow_link(struct dentry *direntry, void **cookie);
-extern int cifs_readlink(struct dentry *direntry, char __user *buffer,
- int buflen);
+extern const char *cifs_get_link(struct dentry *, struct inode *, void **);
extern int cifs_symlink(struct inode *inode, struct dentry *direntry,
const char *symname);
extern int cifs_removexattr(struct dentry *, const char *);
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index e3548f7..6f2439b5 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -627,9 +627,8 @@ cifs_hl_exit:
}

const char *
-cifs_follow_link(struct dentry *direntry, void **cookie)
+cifs_get_link(struct dentry *direntry, struct inode *inode, void **cookie)
{
- struct inode *inode = d_inode(direntry);
int rc = -ENOMEM;
unsigned int xid;
char *full_path = NULL;
@@ -639,6 +638,9 @@ cifs_follow_link(struct dentry *direntry, void **cookie)
struct cifs_tcon *tcon;
struct TCP_Server_Info *server;

+ if (!direntry)
+ return ERR_PTR(-ECHILD);
+
xid = get_xid();

tlink = cifs_sb_tlink(cifs_sb);
diff --git a/fs/coda/cnode.c b/fs/coda/cnode.c
index e37d242..f5872bd 100644
--- a/fs/coda/cnode.c
+++ b/fs/coda/cnode.c
@@ -17,7 +17,7 @@ static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)

static const struct inode_operations coda_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.setattr = coda_setattr,
};
diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c
index ec5c832..b91c01e 100644
--- a/fs/configfs/symlink.c
+++ b/fs/configfs/symlink.c
@@ -279,11 +279,16 @@ static int configfs_getlink(struct dentry *dentry, char * path)

}

-static const char *configfs_follow_link(struct dentry *dentry, void **cookie)
+static const char *configfs_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- unsigned long page = get_zeroed_page(GFP_KERNEL);
+ unsigned long page;
int error;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
+ page = get_zeroed_page(GFP_KERNEL);
if (!page)
return ERR_PTR(-ENOMEM);

@@ -297,7 +302,7 @@ static const char *configfs_follow_link(struct dentry *dentry, void **cookie)
}

const struct inode_operations configfs_symlink_inode_operations = {
- .follow_link = configfs_follow_link,
+ .get_link = configfs_get_link,
.readlink = generic_readlink,
.put_link = free_page_put_link,
.setattr = configfs_setattr,
diff --git a/fs/dcache.c b/fs/dcache.c
index 5c33aeb..d27f090 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1734,7 +1734,7 @@ static unsigned d_flags_for_inode(struct inode *inode)
}

if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
- if (unlikely(inode->i_op->follow_link)) {
+ if (unlikely(inode->i_op->get_link)) {
add_flags = DCACHE_SYMLINK_TYPE;
goto type_determined;
}
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index e2e47ba..5a05559 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -674,10 +674,16 @@ out:
return rc ? ERR_PTR(rc) : buf;
}

-static const char *ecryptfs_follow_link(struct dentry *dentry, void **cookie)
+static const char *ecryptfs_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
size_t len;
- char *buf = ecryptfs_readlink_lower(dentry, &len);
+ char *buf;
+
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
+ buf = ecryptfs_readlink_lower(dentry, &len);
if (IS_ERR(buf))
return buf;
fsstack_copy_attr_atime(d_inode(dentry),
@@ -1095,7 +1101,7 @@ out:

const struct inode_operations ecryptfs_symlink_iops = {
.readlink = generic_readlink,
- .follow_link = ecryptfs_follow_link,
+ .get_link = ecryptfs_get_link,
.put_link = kfree_put_link,
.permission = ecryptfs_permission,
.setattr = ecryptfs_setattr,
diff --git a/fs/ext2/symlink.c b/fs/ext2/symlink.c
index ae17179..4690511 100644
--- a/fs/ext2/symlink.c
+++ b/fs/ext2/symlink.c
@@ -22,7 +22,7 @@

const struct inode_operations ext2_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.setattr = ext2_setattr,
#ifdef CONFIG_EXT2_FS_XATTR
@@ -35,7 +35,7 @@ const struct inode_operations ext2_symlink_inode_operations = {

const struct inode_operations ext2_fast_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = simple_follow_link,
+ .get_link = simple_get_link,
.setattr = ext2_setattr,
#ifdef CONFIG_EXT2_FS_XATTR
.setxattr = generic_setxattr,
diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
index 0e6dc44..3b4bfe2 100644
--- a/fs/ext4/symlink.c
+++ b/fs/ext4/symlink.c
@@ -23,17 +23,20 @@
#include "xattr.h"

#ifdef CONFIG_EXT4_FS_ENCRYPTION
-static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cookie)
+static const char *ext4_encrypted_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
struct page *cpage = NULL;
char *caddr, *paddr = NULL;
struct ext4_str cstr, pstr;
- struct inode *inode = d_inode(dentry);
struct ext4_encrypted_symlink_data *sd;
loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
int res;
u32 plen, max_size = inode->i_sb->s_blocksize;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
res = ext4_get_encryption_info(inode);
if (res)
return ERR_PTR(res);
@@ -87,7 +90,7 @@ errout:

const struct inode_operations ext4_encrypted_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = ext4_encrypted_follow_link,
+ .get_link = ext4_encrypted_get_link,
.put_link = kfree_put_link,
.setattr = ext4_setattr,
.setxattr = generic_setxattr,
@@ -99,7 +102,7 @@ const struct inode_operations ext4_encrypted_symlink_inode_operations = {

const struct inode_operations ext4_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.setattr = ext4_setattr,
.setxattr = generic_setxattr,
@@ -110,7 +113,7 @@ const struct inode_operations ext4_symlink_inode_operations = {

const struct inode_operations ext4_fast_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = simple_follow_link,
+ .get_link = simple_get_link,
.setattr = ext4_setattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 1aea1c3..ced65443 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -315,9 +315,10 @@ fail:
return err;
}

-static const char *f2fs_follow_link(struct dentry *dentry, void **cookie)
+static const char *f2fs_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- const char *link = page_follow_link_light(dentry, cookie);
+ const char *link = page_get_link(dentry, inode, cookie);
if (!IS_ERR(link) && !*link) {
/* this is broken symlink case */
page_put_link(NULL, *cookie);
@@ -924,18 +925,21 @@ static int f2fs_rename2(struct inode *old_dir, struct dentry *old_dentry,
}

#ifdef CONFIG_F2FS_FS_ENCRYPTION
-static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cookie)
+static const char *f2fs_encrypted_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
struct page *cpage = NULL;
char *caddr, *paddr = NULL;
struct f2fs_str cstr;
struct f2fs_str pstr = FSTR_INIT(NULL, 0);
- struct inode *inode = d_inode(dentry);
struct f2fs_encrypted_symlink_data *sd;
loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
u32 max_size = inode->i_sb->s_blocksize;
int res;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
res = f2fs_get_encryption_info(inode);
if (res)
return ERR_PTR(res);
@@ -994,7 +998,7 @@ errout:

const struct inode_operations f2fs_encrypted_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = f2fs_encrypted_follow_link,
+ .get_link = f2fs_encrypted_get_link,
.put_link = kfree_put_link,
.getattr = f2fs_getattr,
.setattr = f2fs_setattr,
@@ -1030,7 +1034,7 @@ const struct inode_operations f2fs_dir_inode_operations = {

const struct inode_operations f2fs_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = f2fs_follow_link,
+ .get_link = f2fs_get_link,
.put_link = page_put_link,
.getattr = f2fs_getattr,
.setattr = f2fs_setattr,
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 5e2e087..148e8ef 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1365,14 +1365,17 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx)
return err;
}

-static const char *fuse_follow_link(struct dentry *dentry, void **cookie)
+static const char *fuse_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- struct inode *inode = d_inode(dentry);
struct fuse_conn *fc = get_fuse_conn(inode);
FUSE_ARGS(args);
char *link;
ssize_t ret;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
link = (char *) __get_free_page(GFP_KERNEL);
if (!link)
return ERR_PTR(-ENOMEM);
@@ -1909,7 +1912,7 @@ static const struct inode_operations fuse_common_inode_operations = {

static const struct inode_operations fuse_symlink_inode_operations = {
.setattr = fuse_setattr,
- .follow_link = fuse_follow_link,
+ .get_link = fuse_get_link,
.put_link = free_page_put_link,
.readlink = generic_readlink,
.getattr = fuse_getattr,
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 063fdfc..10950560 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -1712,24 +1712,29 @@ static int gfs2_rename2(struct inode *odir, struct dentry *odentry,
}

/**
- * gfs2_follow_link - Follow a symbolic link
+ * gfs2_get_link - Follow a symbolic link
* @dentry: The dentry of the link
- * @nd: Data that we pass to vfs_follow_link()
+ * @inode: The inode of the link
+ * @cookie: place to store the information for ->put_link()
*
* This can handle symlinks of any size.
*
* Returns: 0 on success or error code
*/

-static const char *gfs2_follow_link(struct dentry *dentry, void **cookie)
+static const char *gfs2_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- struct gfs2_inode *ip = GFS2_I(d_inode(dentry));
+ struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_holder i_gh;
struct buffer_head *dibh;
unsigned int size;
char *buf;
int error;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &i_gh);
error = gfs2_glock_nq(&i_gh);
if (error) {
@@ -2132,7 +2137,7 @@ const struct inode_operations gfs2_dir_iops = {

const struct inode_operations gfs2_symlink_iops = {
.readlink = generic_readlink,
- .follow_link = gfs2_follow_link,
+ .get_link = gfs2_get_link,
.put_link = kfree_put_link,
.permission = gfs2_permission,
.setattr = gfs2_setattr,
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index 2ac99db..6ce5309 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -892,9 +892,13 @@ static const struct inode_operations hostfs_dir_iops = {
.setattr = hostfs_setattr,
};

-static const char *hostfs_follow_link(struct dentry *dentry, void **cookie)
+static const char *hostfs_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- char *link = __getname();
+ char *link;
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+ link = __getname();
if (link) {
char *path = dentry_name(dentry);
int err = -ENOMEM;
@@ -922,7 +926,7 @@ static void hostfs_put_link(struct inode *unused, void *cookie)

static const struct inode_operations hostfs_link_iops = {
.readlink = generic_readlink,
- .follow_link = hostfs_follow_link,
+ .get_link = hostfs_get_link,
.put_link = hostfs_put_link,
};

diff --git a/fs/jffs2/symlink.c b/fs/jffs2/symlink.c
index 8ce2f24..2cabd64 100644
--- a/fs/jffs2/symlink.c
+++ b/fs/jffs2/symlink.c
@@ -14,7 +14,7 @@
const struct inode_operations jffs2_symlink_inode_operations =
{
.readlink = generic_readlink,
- .follow_link = simple_follow_link,
+ .get_link = simple_get_link,
.setattr = jffs2_setattr,
.setxattr = jffs2_setxattr,
.getxattr = jffs2_getxattr,
diff --git a/fs/jfs/symlink.c b/fs/jfs/symlink.c
index 5929e23..0211328 100644
--- a/fs/jfs/symlink.c
+++ b/fs/jfs/symlink.c
@@ -23,7 +23,7 @@

const struct inode_operations jfs_fast_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = simple_follow_link,
+ .get_link = simple_get_link,
.setattr = jfs_setattr,
.setxattr = jfs_setxattr,
.getxattr = jfs_getxattr,
@@ -33,7 +33,7 @@ const struct inode_operations jfs_fast_symlink_inode_operations = {

const struct inode_operations jfs_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.setattr = jfs_setattr,
.setxattr = jfs_setxattr,
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index db27252..ffae857 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -112,10 +112,15 @@ static int kernfs_getlink(struct dentry *dentry, char *path)
return error;
}

-static const char *kernfs_iop_follow_link(struct dentry *dentry, void **cookie)
+static const char *kernfs_iop_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
int error = -ENOMEM;
- unsigned long page = get_zeroed_page(GFP_KERNEL);
+ unsigned long page;
+
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+ page = get_zeroed_page(GFP_KERNEL);
if (!page)
return ERR_PTR(-ENOMEM);
error = kernfs_getlink(dentry, (char *)page);
@@ -132,7 +137,7 @@ const struct inode_operations kernfs_symlink_iops = {
.getxattr = kernfs_iop_getxattr,
.listxattr = kernfs_iop_listxattr,
.readlink = generic_readlink,
- .follow_link = kernfs_iop_follow_link,
+ .get_link = kernfs_iop_get_link,
.put_link = free_page_put_link,
.setattr = kernfs_iop_setattr,
.getattr = kernfs_iop_getattr,
diff --git a/fs/libfs.c b/fs/libfs.c
index c7cbfb0..8dc37fc 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1092,14 +1092,15 @@ simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
}
EXPORT_SYMBOL(simple_nosetlease);

-const char *simple_follow_link(struct dentry *dentry, void **cookie)
+const char *simple_get_link(struct dentry *dentry, struct inode *inode,
+ void **cookie)
{
- return d_inode(dentry)->i_link;
+ return inode->i_link;
}
-EXPORT_SYMBOL(simple_follow_link);
+EXPORT_SYMBOL(simple_get_link);

const struct inode_operations simple_symlink_inode_operations = {
- .follow_link = simple_follow_link,
+ .get_link = simple_get_link,
.readlink = generic_readlink
};
EXPORT_SYMBOL(simple_symlink_inode_operations);
diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index a28ae96..fced09c 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -435,7 +435,7 @@ static const struct address_space_operations minix_aops = {

static const struct inode_operations minix_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.getattr = minix_getattr,
};
diff --git a/fs/namei.c b/fs/namei.c
index 924c6a5e..089c37f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -842,7 +842,7 @@ static inline void path_to_nameidata(const struct path *path,
}

/*
- * Helper to directly jump to a known parsed path from ->follow_link,
+ * Helper to directly jump to a known parsed path from ->get_link,
* caller must have taken a reference to path beforehand.
*/
void nd_jump_link(struct path *path)
@@ -1005,10 +1005,18 @@ const char *get_link(struct nameidata *nd)
res = inode->i_link;
if (!res) {
if (nd->flags & LOOKUP_RCU) {
- if (unlikely(unlazy_walk(nd, NULL, 0)))
- return ERR_PTR(-ECHILD);
+ res = inode->i_op->get_link(NULL, inode,
+ &last->cookie);
+ if (res == ERR_PTR(-ECHILD)) {
+ if (unlikely(unlazy_walk(nd, NULL, 0)))
+ return ERR_PTR(-ECHILD);
+ res = inode->i_op->get_link(dentry, inode,
+ &last->cookie);
+ }
+ } else {
+ res = inode->i_op->get_link(dentry, inode,
+ &last->cookie);
}
- res = inode->i_op->follow_link(dentry, &last->cookie);
if (IS_ERR_OR_NULL(res)) {
last->cookie = NULL;
return res;
@@ -4496,8 +4504,8 @@ EXPORT_SYMBOL(readlink_copy);

/*
* A helper for ->readlink(). This should be used *ONLY* for symlinks that
- * have ->follow_link() touching nd only in nd_set_link(). Using (or not
- * using) it for any given inode is up to filesystem.
+ * have ->get_link() not calling nd_jump_link(). Using (or not using) it
+ * for any given inode is up to filesystem.
*/
int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
{
@@ -4507,7 +4515,7 @@ int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
int res;

if (!link) {
- link = inode->i_op->follow_link(dentry, &cookie);
+ link = inode->i_op->get_link(dentry, inode, &cookie);
if (IS_ERR(link))
return PTR_ERR(link);
}
@@ -4519,26 +4527,27 @@ int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
EXPORT_SYMBOL(generic_readlink);

/* get the link contents into pagecache */
-static const char *page_getlink(struct dentry * dentry, void **cookie)
+const char *page_get_link(struct dentry *dentry, struct inode *inode,
+ void **cookie)
{
char *kaddr;
struct page *page;
- struct address_space *mapping = dentry->d_inode->i_mapping;
+ struct address_space *mapping = inode->i_mapping;
+
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
page = read_mapping_page(mapping, 0, NULL);
if (IS_ERR(page))
return (char*)page;
*cookie = page;
BUG_ON(mapping_gfp_mask(mapping) & __GFP_HIGHMEM);
kaddr = page_address(page);
- nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1);
+ nd_terminate_link(kaddr, inode->i_size, PAGE_SIZE - 1);
return kaddr;
}

-const char *page_follow_link_light(struct dentry *dentry, void **cookie)
-{
- return page_getlink(dentry, cookie);
-}
-EXPORT_SYMBOL(page_follow_link_light);
+EXPORT_SYMBOL(page_get_link);

void page_put_link(struct inode *unused, void *cookie)
{
@@ -4550,7 +4559,9 @@ EXPORT_SYMBOL(page_put_link);
int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
{
void *cookie = NULL;
- int res = readlink_copy(buffer, buflen, page_getlink(dentry, &cookie));
+ int res = readlink_copy(buffer, buflen,
+ page_get_link(dentry, d_inode(dentry),
+ &cookie));
if (cookie)
page_put_link(NULL, cookie);
return res;
@@ -4601,7 +4612,7 @@ EXPORT_SYMBOL(page_symlink);

const struct inode_operations page_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
};
EXPORT_SYMBOL(page_symlink_inode_operations);
diff --git a/fs/ncpfs/inode.c b/fs/ncpfs/inode.c
index 2bb5d3d3..028cacf 100644
--- a/fs/ncpfs/inode.c
+++ b/fs/ncpfs/inode.c
@@ -244,7 +244,7 @@ static void ncp_set_attr(struct inode *inode, struct ncp_entry_info *nwinfo)
#if defined(CONFIG_NCPFS_EXTRAS) || defined(CONFIG_NCPFS_NFS_NS)
static const struct inode_operations ncp_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.setattr = ncp_notify_change,
};
diff --git a/fs/nfs/symlink.c b/fs/nfs/symlink.c
index abd93bf..8ade8a8 100644
--- a/fs/nfs/symlink.c
+++ b/fs/nfs/symlink.c
@@ -42,12 +42,15 @@ error:
return -EIO;
}

-static const char *nfs_follow_link(struct dentry *dentry, void **cookie)
+static const char *nfs_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- struct inode *inode = d_inode(dentry);
struct page *page;
void *err;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping));
if (err)
return err;
@@ -64,7 +67,7 @@ static const char *nfs_follow_link(struct dentry *dentry, void **cookie)
*/
const struct inode_operations nfs_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = nfs_follow_link,
+ .get_link = nfs_get_link,
.put_link = page_put_link,
.getattr = nfs_getattr,
.setattr = nfs_setattr,
diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
index c7c4df5..8daa40f 100644
--- a/fs/nilfs2/namei.c
+++ b/fs/nilfs2/namei.c
@@ -569,7 +569,7 @@ const struct inode_operations nilfs_special_inode_operations = {

const struct inode_operations nilfs_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.permission = nilfs_permission,
};
diff --git a/fs/ocfs2/symlink.c b/fs/ocfs2/symlink.c
index 66edce7..b4e79bc 100644
--- a/fs/ocfs2/symlink.c
+++ b/fs/ocfs2/symlink.c
@@ -88,7 +88,7 @@ const struct address_space_operations ocfs2_fast_symlink_aops = {

const struct inode_operations ocfs2_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.getattr = ocfs2_getattr,
.setattr = ocfs2_setattr,
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index ec0c2a0..4c24a44 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -140,17 +140,21 @@ struct ovl_link_data {
void *cookie;
};

-static const char *ovl_follow_link(struct dentry *dentry, void **cookie)
+static const char *ovl_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
struct dentry *realdentry;
struct inode *realinode;
struct ovl_link_data *data = NULL;
const char *ret;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
realdentry = ovl_dentry_real(dentry);
realinode = realdentry->d_inode;

- if (WARN_ON(!realinode->i_op->follow_link))
+ if (WARN_ON(!realinode->i_op->get_link))
return ERR_PTR(-EPERM);

if (realinode->i_op->put_link) {
@@ -160,7 +164,7 @@ static const char *ovl_follow_link(struct dentry *dentry, void **cookie)
data->realdentry = realdentry;
}

- ret = realinode->i_op->follow_link(realdentry, cookie);
+ ret = realinode->i_op->get_link(realdentry, realinode, cookie);
if (IS_ERR_OR_NULL(ret)) {
kfree(data);
return ret;
@@ -381,7 +385,7 @@ static const struct inode_operations ovl_file_inode_operations = {

static const struct inode_operations ovl_symlink_inode_operations = {
.setattr = ovl_setattr,
- .follow_link = ovl_follow_link,
+ .get_link = ovl_get_link,
.put_link = ovl_put_link,
.readlink = ovl_readlink,
.getattr = ovl_getattr,
diff --git a/fs/proc/base.c b/fs/proc/base.c
index bd3e9e6..1a489e2 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1564,12 +1564,15 @@ static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
return -ENOENT;
}

-static const char *proc_pid_follow_link(struct dentry *dentry, void **cookie)
+static const char *proc_pid_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- struct inode *inode = d_inode(dentry);
struct path path;
int error = -EACCES;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
/* Are we allowed to snoop on the tasks file descriptors? */
if (!proc_fd_access_allowed(inode))
goto out;
@@ -1630,7 +1633,7 @@ out:

const struct inode_operations proc_pid_link_inode_operations = {
.readlink = proc_pid_readlink,
- .follow_link = proc_pid_follow_link,
+ .get_link = proc_pid_get_link,
.setattr = proc_setattr,
};

@@ -1895,7 +1898,7 @@ static const struct dentry_operations tid_map_files_dentry_operations = {
.d_delete = pid_delete_dentry,
};

-static int proc_map_files_get_link(struct dentry *dentry, struct path *path)
+static int map_files_get_link(struct dentry *dentry, struct path *path)
{
unsigned long vm_start, vm_end;
struct vm_area_struct *vma;
@@ -1945,20 +1948,21 @@ struct map_files_info {
* path to the file in question.
*/
static const char *
-proc_map_files_follow_link(struct dentry *dentry, void **cookie)
+proc_map_files_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
if (!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);

- return proc_pid_follow_link(dentry, NULL);
+ return proc_pid_get_link(dentry, inode, NULL);
}

/*
- * Identical to proc_pid_link_inode_operations except for follow_link()
+ * Identical to proc_pid_link_inode_operations except for get_link()
*/
static const struct inode_operations proc_map_files_link_inode_operations = {
.readlink = proc_pid_readlink,
- .follow_link = proc_map_files_follow_link,
+ .get_link = proc_map_files_get_link,
.setattr = proc_setattr,
};

@@ -1975,7 +1979,7 @@ proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
return -ENOENT;

ei = PROC_I(inode);
- ei->op.proc_get_link = proc_map_files_get_link;
+ ei->op.proc_get_link = map_files_get_link;

inode->i_op = &proc_map_files_link_inode_operations;
inode->i_size = 64;
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index bd95b9f..10360b2 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -393,9 +393,10 @@ static const struct file_operations proc_reg_file_ops_no_compat = {
};
#endif

-static const char *proc_follow_link(struct dentry *dentry, void **cookie)
+static const char *proc_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- struct proc_dir_entry *pde = PDE(d_inode(dentry));
+ struct proc_dir_entry *pde = PDE(inode);
if (unlikely(!use_pde(pde)))
return ERR_PTR(-EINVAL);
*cookie = pde;
@@ -409,7 +410,7 @@ static void proc_put_link(struct inode *unused, void *p)

const struct inode_operations proc_link_inode_operations = {
.readlink = generic_readlink,
- .follow_link = proc_follow_link,
+ .get_link = proc_get_link,
.put_link = proc_put_link,
};

diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index f6e8354..63861c1 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -30,14 +30,17 @@ static const struct proc_ns_operations *ns_entries[] = {
&mntns_operations,
};

-static const char *proc_ns_follow_link(struct dentry *dentry, void **cookie)
+static const char *proc_ns_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
- struct inode *inode = d_inode(dentry);
const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
struct task_struct *task;
struct path ns_path;
void *error = ERR_PTR(-EACCES);

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
task = get_proc_task(inode);
if (!task)
return error;
@@ -74,7 +77,7 @@ static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int bufl

static const struct inode_operations proc_ns_link_inode_operations = {
.readlink = proc_ns_readlink,
- .follow_link = proc_ns_follow_link,
+ .get_link = proc_ns_get_link,
.setattr = proc_setattr,
};

diff --git a/fs/proc/self.c b/fs/proc/self.c
index 113b8d0..bc599fb 100644
--- a/fs/proc/self.c
+++ b/fs/proc/self.c
@@ -18,12 +18,15 @@ static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
return readlink_copy(buffer, buflen, tmp);
}

-static const char *proc_self_follow_link(struct dentry *dentry, void **cookie)
+static const char *proc_self_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
pid_t tgid = task_tgid_nr_ns(current, ns);
char *name;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
if (!tgid)
return ERR_PTR(-ENOENT);
/* 11 for max length of signed int in decimal + NULL term */
@@ -36,7 +39,7 @@ static const char *proc_self_follow_link(struct dentry *dentry, void **cookie)

static const struct inode_operations proc_self_inode_operations = {
.readlink = proc_self_readlink,
- .follow_link = proc_self_follow_link,
+ .get_link = proc_self_get_link,
.put_link = kfree_put_link,
};

diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c
index 947b0f4..1c78507 100644
--- a/fs/proc/thread_self.c
+++ b/fs/proc/thread_self.c
@@ -19,13 +19,16 @@ static int proc_thread_self_readlink(struct dentry *dentry, char __user *buffer,
return readlink_copy(buffer, buflen, tmp);
}

-static const char *proc_thread_self_follow_link(struct dentry *dentry, void **cookie)
+static const char *proc_thread_self_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
struct pid_namespace *ns = dentry->d_sb->s_fs_info;
pid_t tgid = task_tgid_nr_ns(current, ns);
pid_t pid = task_pid_nr_ns(current, ns);
char *name;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
if (!pid)
return ERR_PTR(-ENOENT);
name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF, GFP_KERNEL);
@@ -37,7 +40,7 @@ static const char *proc_thread_self_follow_link(struct dentry *dentry, void **co

static const struct inode_operations proc_thread_self_inode_operations = {
.readlink = proc_thread_self_readlink,
- .follow_link = proc_thread_self_follow_link,
+ .get_link = proc_thread_self_get_link,
.put_link = kfree_put_link,
};

diff --git a/fs/reiserfs/namei.c b/fs/reiserfs/namei.c
index e78f59b..091e2ac 100644
--- a/fs/reiserfs/namei.c
+++ b/fs/reiserfs/namei.c
@@ -1665,7 +1665,7 @@ const struct inode_operations reiserfs_dir_inode_operations = {
*/
const struct inode_operations reiserfs_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.setattr = reiserfs_setattr,
.setxattr = reiserfs_setxattr,
diff --git a/fs/squashfs/symlink.c b/fs/squashfs/symlink.c
index 12806df..7c635a5 100644
--- a/fs/squashfs/symlink.c
+++ b/fs/squashfs/symlink.c
@@ -119,7 +119,7 @@ const struct address_space_operations squashfs_symlink_aops = {

const struct inode_operations squashfs_symlink_inode_ops = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.getxattr = generic_getxattr,
.listxattr = squashfs_listxattr
diff --git a/fs/sysv/inode.c b/fs/sysv/inode.c
index 9a92895..cc7f559 100644
--- a/fs/sysv/inode.c
+++ b/fs/sysv/inode.c
@@ -146,7 +146,7 @@ static inline void write3byte(struct sysv_sb_info *sbi,

static const struct inode_operations sysv_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .get_link = page_get_link,
.put_link = page_put_link,
.getattr = sysv_getattr,
};
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 0edc128..eff6280 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1608,7 +1608,7 @@ const struct inode_operations ubifs_file_inode_operations = {

const struct inode_operations ubifs_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = simple_follow_link,
+ .get_link = simple_get_link,
.setattr = ubifs_setattr,
.getattr = ubifs_getattr,
.setxattr = ubifs_setxattr,
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 245268a..f638fd5 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -414,13 +414,17 @@ xfs_vn_rename(
* uio is kmalloced for this reason...
*/
STATIC const char *
-xfs_vn_follow_link(
+xfs_vn_get_link(
struct dentry *dentry,
+ struct inode *inode,
void **cookie)
{
char *link;
int error = -ENOMEM;

+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
link = kmalloc(MAXPATHLEN+1, GFP_KERNEL);
if (!link)
goto out_err;
@@ -1172,7 +1176,7 @@ static const struct inode_operations xfs_dir_ci_inode_operations = {

static const struct inode_operations xfs_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = xfs_vn_follow_link,
+ .get_link = xfs_vn_get_link,
.put_link = kfree_put_link,
.getattr = xfs_vn_getattr,
.setattr = xfs_vn_setattr,
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0b8d4d7..e2be8e9 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1633,7 +1633,7 @@ struct file_operations {

struct inode_operations {
struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
- const char * (*follow_link) (struct dentry *, void **);
+ const char * (*get_link) (struct dentry *, struct inode *, void **);
int (*permission) (struct inode *, int);
struct posix_acl * (*get_acl)(struct inode *, int);

@@ -2736,7 +2736,7 @@ extern const struct file_operations generic_ro_fops;

extern int readlink_copy(char __user *, int, const char *);
extern int page_readlink(struct dentry *, char __user *, int);
-extern const char *page_follow_link_light(struct dentry *, void **);
+extern const char *page_get_link(struct dentry *, struct inode *, void **);
extern void page_put_link(struct inode *, void *);
extern int __page_symlink(struct inode *inode, const char *symname, int len,
int nofs);
@@ -2754,7 +2754,7 @@ void __inode_sub_bytes(struct inode *inode, loff_t bytes);
void inode_sub_bytes(struct inode *inode, loff_t bytes);
loff_t inode_get_bytes(struct inode *inode);
void inode_set_bytes(struct inode *inode, loff_t bytes);
-const char *simple_follow_link(struct dentry *, void **);
+const char *simple_get_link(struct dentry *, struct inode *, void **);
extern const struct inode_operations simple_symlink_inode_operations;

extern int iterate_dir(struct file *, struct dir_context *);
diff --git a/mm/shmem.c b/mm/shmem.c
index 9e701be..e8220cf 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2496,10 +2496,14 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
return 0;
}

-static const char *shmem_follow_link(struct dentry *dentry, void **cookie)
+static const char *shmem_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
struct page *page = NULL;
- int error = shmem_getpage(d_inode(dentry), 0, &page, SGP_READ, NULL);
+ int error;
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+ error = shmem_getpage(inode, 0, &page, SGP_READ, NULL);
if (error)
return ERR_PTR(error);
unlock_page(page);
@@ -2656,7 +2660,7 @@ static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)

static const struct inode_operations shmem_short_symlink_operations = {
.readlink = generic_readlink,
- .follow_link = simple_follow_link,
+ .get_link = simple_get_link,
#ifdef CONFIG_TMPFS_XATTR
.setxattr = shmem_setxattr,
.getxattr = shmem_getxattr,
@@ -2667,7 +2671,7 @@ static const struct inode_operations shmem_short_symlink_operations = {

static const struct inode_operations shmem_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = shmem_follow_link,
+ .get_link = shmem_get_link,
.put_link = shmem_put_link,
#ifdef CONFIG_TMPFS_XATTR
.setxattr = shmem_setxattr,
--
2.1.4

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